2 * sgen-los.c: Simple generational GC.
5 * Paolo Molaro (lupus@ximian.com)
7 * Copyright 2005-2010 Novell, Inc (http://www.novell.com)
9 * Thread start/stop adapted from Boehm's GC:
10 * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
11 * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
12 * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
13 * Copyright (c) 2000-2004 by Hewlett-Packard Company. All rights reserved.
15 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
16 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
18 * Permission is hereby granted to use or copy this program
19 * for any purpose, provided the above notices are retained on all copies.
20 * Permission to modify the code and to distribute modified code is granted,
21 * provided the above notices are retained, and a notice that the code was
22 * modified is included with the above copyright notice.
25 * Copyright 2001-2003 Ximian, Inc
26 * Copyright 2003-2010 Novell, Inc.
28 * Permission is hereby granted, free of charge, to any person obtaining
29 * a copy of this software and associated documentation files (the
30 * "Software"), to deal in the Software without restriction, including
31 * without limitation the rights to use, copy, modify, merge, publish,
32 * distribute, sublicense, and/or sell copies of the Software, and to
33 * permit persons to whom the Software is furnished to do so, subject to
34 * the following conditions:
36 * The above copyright notice and this permission notice shall be
37 * included in all copies or substantial portions of the Software.
39 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
40 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
41 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
42 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
43 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
44 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
45 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
52 #include "metadata/sgen-gc.h"
53 #include "metadata/sgen-protocol.h"
54 #include "metadata/sgen-cardtable.h"
55 #include "metadata/sgen-memory-governor.h"
56 #include "utils/mono-mmap.h"
58 #define LOS_SECTION_SIZE (1024 * 1024)
61 * This shouldn't be much smaller or larger than MAX_SMALL_OBJ_SIZE.
62 * Must be at least sizeof (LOSSection).
64 #define LOS_CHUNK_SIZE 4096
65 #define LOS_CHUNK_BITS 12
67 /* Largest object that can be allocated in a section. */
68 #define LOS_SECTION_OBJECT_LIMIT (LOS_SECTION_SIZE - LOS_CHUNK_SIZE - sizeof (LOSObject))
69 //#define LOS_SECTION_OBJECT_LIMIT 0
70 #define LOS_SECTION_NUM_CHUNKS ((LOS_SECTION_SIZE >> LOS_CHUNK_BITS) - 1)
72 #define LOS_SECTION_FOR_OBJ(obj) ((LOSSection*)((mword)(obj) & ~(mword)(LOS_SECTION_SIZE - 1)))
73 #define LOS_CHUNK_INDEX(obj,section) (((char*)(obj) - (char*)(section)) >> LOS_CHUNK_BITS)
75 #define LOS_NUM_FAST_SIZES 32
77 typedef struct _LOSFreeChunks LOSFreeChunks;
78 struct _LOSFreeChunks {
79 LOSFreeChunks *next_size;
83 typedef struct _LOSSection LOSSection;
87 unsigned char *free_chunk_map;
90 LOSObject *los_object_list = NULL;
91 mword los_memory_usage = 0;
93 static LOSSection *los_sections = NULL;
94 static LOSFreeChunks *los_fast_free_lists [LOS_NUM_FAST_SIZES]; /* 0 is for larger sizes */
95 static mword los_num_objects = 0;
96 static int los_num_sections = 0;
99 //#define LOS_CONSISTENCY_CHECK
103 #define LOS_SEGMENT_SIZE (4096 * 1024)
105 static char *los_segment = NULL;
106 static int los_segment_index = 0;
109 #ifdef LOS_CONSISTENCY_CHECK
111 los_consistency_check (void)
116 mword memory_usage = 0;
118 for (obj = los_object_list; obj; obj = obj->next) {
119 char *end = obj->data + obj->size;
120 int start_index, num_chunks;
122 memory_usage += obj->size;
124 if (obj->size > LOS_SECTION_OBJECT_LIMIT)
127 section = LOS_SECTION_FOR_OBJ (obj);
129 g_assert (end <= (char*)section + LOS_SECTION_SIZE);
131 start_index = LOS_CHUNK_INDEX (obj, section);
132 num_chunks = (obj->size + sizeof (LOSObject) + LOS_CHUNK_SIZE - 1) >> LOS_CHUNK_BITS;
133 for (i = start_index; i < start_index + num_chunks; ++i)
134 g_assert (!section->free_chunk_map [i]);
137 for (i = 0; i < LOS_NUM_FAST_SIZES; ++i) {
138 LOSFreeChunks *size_chunks;
139 for (size_chunks = los_fast_free_lists [i]; size_chunks; size_chunks = size_chunks->next_size) {
140 LOSSection *section = LOS_SECTION_FOR_OBJ (size_chunks);
141 int j, num_chunks, start_index;
144 g_assert (size_chunks->size >= LOS_NUM_FAST_SIZES * LOS_CHUNK_SIZE);
146 g_assert (size_chunks->size == i * LOS_CHUNK_SIZE);
148 num_chunks = size_chunks->size >> LOS_CHUNK_BITS;
149 start_index = LOS_CHUNK_INDEX (size_chunks, section);
150 for (j = start_index; j < start_index + num_chunks; ++j)
151 g_assert (section->free_chunk_map [j]);
155 g_assert (los_memory_usage == memory_usage);
160 add_free_chunk (LOSFreeChunks *free_chunks, size_t size)
162 int num_chunks = size >> LOS_CHUNK_BITS;
164 free_chunks->size = size;
166 if (num_chunks >= LOS_NUM_FAST_SIZES)
168 free_chunks->next_size = los_fast_free_lists [num_chunks];
169 los_fast_free_lists [num_chunks] = free_chunks;
172 static LOSFreeChunks*
173 get_from_size_list (LOSFreeChunks **list, size_t size)
175 LOSFreeChunks *free_chunks = NULL;
177 int num_chunks, i, start_index;
179 g_assert ((size & (LOS_CHUNK_SIZE - 1)) == 0);
183 if (free_chunks->size >= size)
185 list = &(*list)->next_size;
191 *list = free_chunks->next_size;
193 if (free_chunks->size > size)
194 add_free_chunk ((LOSFreeChunks*)((char*)free_chunks + size), free_chunks->size - size);
196 num_chunks = size >> LOS_CHUNK_BITS;
198 section = LOS_SECTION_FOR_OBJ (free_chunks);
200 start_index = LOS_CHUNK_INDEX (free_chunks, section);
201 for (i = start_index; i < start_index + num_chunks; ++i) {
202 g_assert (section->free_chunk_map [i]);
203 section->free_chunk_map [i] = 0;
206 section->num_free_chunks -= size >> LOS_CHUNK_BITS;
207 g_assert (section->num_free_chunks >= 0);
213 get_los_section_memory (size_t size)
216 LOSFreeChunks *free_chunks;
219 size += LOS_CHUNK_SIZE - 1;
220 size &= ~(LOS_CHUNK_SIZE - 1);
222 num_chunks = size >> LOS_CHUNK_BITS;
224 g_assert (size > 0 && size - sizeof (LOSObject) <= LOS_SECTION_OBJECT_LIMIT);
225 g_assert (num_chunks > 0);
228 if (num_chunks >= LOS_NUM_FAST_SIZES) {
229 free_chunks = get_from_size_list (&los_fast_free_lists [0], size);
232 for (i = num_chunks; i < LOS_NUM_FAST_SIZES; ++i) {
233 free_chunks = get_from_size_list (&los_fast_free_lists [i], size);
238 free_chunks = get_from_size_list (&los_fast_free_lists [0], size);
242 return (LOSObject*)free_chunks;
244 if (!sgen_memgov_try_alloc_space (LOS_SECTION_SIZE, SPACE_LOS))
247 section = sgen_alloc_os_memory_aligned (LOS_SECTION_SIZE, LOS_SECTION_SIZE, TRUE);
252 free_chunks = (LOSFreeChunks*)((char*)section + LOS_CHUNK_SIZE);
253 free_chunks->size = LOS_SECTION_SIZE - LOS_CHUNK_SIZE;
254 free_chunks->next_size = los_fast_free_lists [0];
255 los_fast_free_lists [0] = free_chunks;
257 section->num_free_chunks = LOS_SECTION_NUM_CHUNKS;
259 section->free_chunk_map = (unsigned char*)section + sizeof (LOSSection);
260 g_assert (sizeof (LOSSection) + LOS_SECTION_NUM_CHUNKS + 1 <= LOS_CHUNK_SIZE);
261 section->free_chunk_map [0] = 0;
262 memset (section->free_chunk_map + 1, 1, LOS_SECTION_NUM_CHUNKS);
264 section->next = los_sections;
265 los_sections = section;
273 free_los_section_memory (LOSObject *obj, size_t size)
275 LOSSection *section = LOS_SECTION_FOR_OBJ (obj);
276 int num_chunks, i, start_index;
278 size += LOS_CHUNK_SIZE - 1;
279 size &= ~(LOS_CHUNK_SIZE - 1);
281 num_chunks = size >> LOS_CHUNK_BITS;
283 g_assert (size > 0 && size - sizeof (LOSObject) <= LOS_SECTION_OBJECT_LIMIT);
284 g_assert (num_chunks > 0);
286 section->num_free_chunks += num_chunks;
287 g_assert (section->num_free_chunks <= LOS_SECTION_NUM_CHUNKS);
290 * We could free the LOS section here if it's empty, but we
291 * can't unless we also remove its free chunks from the fast
292 * free lists. Instead, we do it in los_sweep().
295 start_index = LOS_CHUNK_INDEX (obj, section);
296 for (i = start_index; i < start_index + num_chunks; ++i) {
297 g_assert (!section->free_chunk_map [i]);
298 section->free_chunk_map [i] = 1;
301 add_free_chunk ((LOSFreeChunks*)obj, size);
307 sgen_los_free_object (LOSObject *obj)
310 size_t size = obj->size;
311 DEBUG (4, fprintf (gc_debug_file, "Freed large object %p, size %lu\n", obj->data, (unsigned long)obj->size));
312 binary_protocol_empty (obj->data, obj->size);
314 los_memory_usage -= size;
320 if (size > LOS_SECTION_OBJECT_LIMIT) {
322 pagesize = mono_pagesize ();
323 size += sizeof (LOSObject);
324 size += pagesize - 1;
325 size &= ~(pagesize - 1);
326 sgen_free_os_memory (obj, size);
327 sgen_memgov_release_space (size, SPACE_LOS);
329 free_los_section_memory (obj, size + sizeof (LOSObject));
330 #ifdef LOS_CONSISTENCY_CHECKS
331 los_consistency_check ();
339 * Objects with size >= MAX_SMALL_SIZE are allocated in the large object space.
340 * They are currently kept track of with a linked list.
341 * They don't move, so there is no need to pin them during collection
342 * and we avoid the memcpy overhead.
345 sgen_los_alloc_large_inner (MonoVTable *vtable, size_t size)
347 LOSObject *obj = NULL;
350 g_assert (size > SGEN_MAX_SMALL_OBJ_SIZE);
354 los_segment = sgen_alloc_os_memory (LOS_SEGMENT_SIZE, TRUE);
355 los_segment_index = ALIGN_UP (los_segment_index);
357 obj = (LOSObject*)(los_segment + los_segment_index);
358 los_segment_index += size + sizeof (LOSObject);
359 g_assert (los_segment_index <= LOS_SEGMENT_SIZE);
361 sgen_ensure_free_space (size);
364 obj = malloc (size + sizeof (LOSObject));
365 memset (obj, 0, size + sizeof (LOSObject));
367 if (size > LOS_SECTION_OBJECT_LIMIT) {
368 size_t alloc_size = size;
370 pagesize = mono_pagesize ();
371 alloc_size += sizeof (LOSObject);
372 alloc_size += pagesize - 1;
373 alloc_size &= ~(pagesize - 1);
374 if (sgen_memgov_try_alloc_space (alloc_size, SPACE_LOS)) {
375 obj = sgen_alloc_os_memory (alloc_size, TRUE);
377 obj->huge_object = TRUE;
380 obj = get_los_section_memory (size + sizeof (LOSObject));
382 memset (obj, 0, size + sizeof (LOSObject));
388 g_assert (!((mword)obj->data & (SGEN_ALLOC_ALIGN - 1)));
390 vtslot = (void**)obj->data;
392 sgen_update_heap_boundaries ((mword)obj->data, (mword)obj->data + size);
393 obj->next = los_object_list;
394 los_object_list = obj;
395 los_memory_usage += size;
397 DEBUG (4, fprintf (gc_debug_file, "Allocated large object %p, vtable: %p (%s), size: %zd\n", obj->data, vtable, vtable->klass->name, size));
398 binary_protocol_alloc (obj->data, vtable, size);
400 #ifdef LOS_CONSISTENCY_CHECK
401 los_consistency_check ();
408 sgen_los_sweep (void)
410 LOSSection *section, *prev;
412 int num_sections = 0;
414 for (i = 0; i < LOS_NUM_FAST_SIZES; ++i)
415 los_fast_free_lists [i] = NULL;
418 section = los_sections;
420 if (section->num_free_chunks == LOS_SECTION_NUM_CHUNKS) {
421 LOSSection *next = section->next;
426 sgen_free_os_memory (section, LOS_SECTION_SIZE);
427 sgen_memgov_release_space (LOS_SECTION_SIZE, SPACE_LOS);
433 for (i = 0; i <= LOS_SECTION_NUM_CHUNKS; ++i) {
434 if (section->free_chunk_map [i]) {
436 for (j = i + 1; j <= LOS_SECTION_NUM_CHUNKS && section->free_chunk_map [j]; ++j)
438 add_free_chunk ((LOSFreeChunks*)((char*)section + (i << LOS_CHUNK_BITS)), (j - i) << LOS_CHUNK_BITS);
444 section = section->next;
449 #ifdef LOS_CONSISTENCY_CHECK
450 los_consistency_check ();
454 g_print ("LOS sections: %d objects: %d usage: %d\n", num_sections, los_num_objects, los_memory_usage);
455 for (i = 0; i < LOS_NUM_FAST_SIZES; ++i) {
457 LOSFreeChunks *free_chunks;
458 for (free_chunks = los_fast_free_lists [i]; free_chunks; free_chunks = free_chunks->next_size)
460 g_print (" %d: %d\n", i, num_chunks);
464 g_assert (los_num_sections == num_sections);
468 sgen_ptr_is_in_los (char *ptr, char **start)
473 for (obj = los_object_list; obj; obj = obj->next) {
474 char *end = obj->data + obj->size;
476 if (ptr >= obj->data && ptr < end) {
485 sgen_los_iterate_objects (IterateObjectCallbackFunc cb, void *user_data)
489 for (obj = los_object_list; obj; obj = obj->next)
490 cb (obj->data, obj->size, user_data);
494 sgen_los_is_valid_object (char *object)
498 for (obj = los_object_list; obj; obj = obj->next) {
499 if (obj->data == object)
506 mono_sgen_los_describe_pointer (char *ptr)
510 for (obj = los_object_list; obj; obj = obj->next) {
512 if (obj->data > ptr || obj->data + obj->size <= ptr)
515 if (obj->size > LOS_SECTION_OBJECT_LIMIT)
516 fprintf (gc_debug_file, "huge-los-ptr ");
518 fprintf (gc_debug_file, "los-ptr ");
520 vtable = (MonoVTable*)SGEN_LOAD_VTABLE (obj->data);
522 if (obj->data == ptr)
523 fprintf (gc_debug_file, "(object %s.%s size %d)",
524 vtable->klass->name_space, vtable->klass->name, (int)obj->size);
526 fprintf (gc_debug_file, "(interior-ptr offset %td of %p (%s.%s) size %d)",
527 ptr - obj->data, obj->data,
528 vtable->klass->name_space, vtable->klass->name, (int)obj->size);
536 sgen_los_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
539 for (obj = los_object_list; obj; obj = obj->next) {
540 MonoVTable *vt = (MonoVTable*)SGEN_LOAD_VTABLE (obj->data);
541 if (SGEN_VTABLE_HAS_REFERENCES (vt))
542 callback ((mword)obj->data, (mword)obj->size);
546 #ifdef SGEN_HAVE_CARDTABLE
548 sgen_los_scan_card_table (SgenGrayQueue *queue)
552 for (obj = los_object_list; obj; obj = obj->next) {
553 sgen_cardtable_scan_object (obj->data, obj->size, NULL, queue);
558 #endif /* HAVE_SGEN_GC */